The present invention relates to the recovery of metals from their sulfide ores.
Conventional processing of metal sulfide ores such as copper sulfide includes first subjecting the sulfides to concentration procedures such as flotation and then roasting the concentrates to produce a matte which is reduced to impure metallic metal which is then refined to a desired purity. In this pyrometallurgical technique, the sulfur values in the concentrates form gaseous sulfur oxides during the roasting phase which, when released to the atmosphere, cause significant air pollution. There are strict environmental standards for minimizing air pollution of this type. Accordingly, there is a need for economical alternative methods for reducing sulfide ores without producing harmful sulfur oxides.